Electromagnetic audio pickup for stringed musical instruments, with volume control means, and suitable for use with any type strings

ABSTRACT

Basically, in a stringed musical instrument comprising a resonator, top, or belly with strings tensioned between tuning means, string supporting means, and string anchoring means; the improvement comprising an electromagnetic audio pickup suitable for use with any type strings. Said pickup comprises a magnet secured to the said resonator, top, or belly, and a hollow core coil which is magnetically linked to the said magnet so that the magnetic fields aid, and the said coil is mounted to the instrument back or equivalent thereof in a fixed or adjustable relationship to the magnet secured to the resonator, top, or belly.

United States Patent Broussard [54] ELECTROMAGNETIC AUDIO PICKUP FORSTRINGED MUSICAL INSTRUMENTS, WITH VOLUME CONTROL MEANS, AND SUITABLEFOR USE WITH ANY TYPE STRINGS [4 1 June 6,1972

2,020,557 Loar "84/1 .16 2,025,875 12/1935 Loar ...84/1.l5 2,048,5157/1936 Pfeil ..84/l.l5 2,171,430 8/1939 Kjslingbury ..84/l l 5 2,225,19512/1940 Miessner ...84/l.16 3,003,382 10/1961 Fender ..84/l.l6 3,539,70011/1970 Johnson ..84/l 15 X Primary Examiner-Lewis H. Myers AssistantExaminer-U. Weldon [57] ABSTRACT Basically, in a stringed musicalinstrument comprising a resonator, top, or belly with strings tensionedbetween tuning means, string supporting means, and string anchoringmeans;

the improvement comprising an electromagnetic audio pickup suitable foruse with any type strings. Said pickup comprises a magnet secured to thesaid resonator, top, or belly, and a hollow core coil which ismagnetically linked to the said magnet so that the magnetic fields aid,and the said coil is mounted to the instrument back or equivalentthereof in a fixed or adjustable relationship to the magnet secured tothe resonator, top, or belly.

10 Claims, 5 Drawing Figures W 1 E E E 4 p 5 15 ELECTROMAGNETIC AUDIOPICKUP FOR STRINGE) MUSICAL INSTRUMENTS, WITI-I VOLUME CONTROL MEANS,AND SUITABLE FOR USE WITH ANY TYPE STRINGS The present invention relatesto Stringed musical instruments such as the guitar, the mandolin, thebanjo, the violin, the piano, and related instruments.

Conventional pickups for such instruments have been constructedrequiring a large mounting hole, and may not use non-magnetic strings,and/or may require the use of costly magnetic strings. Prior art maythus be susceptible to substantial improvement.

It is therefore an object of the present invention to provide anelectromagnetic audio pickup which will reproduce accurately the soundof steel, special alloy, bronze, aluminum, copper, nylon, and/or anytype of strings.

Another object of the present invention is to provide a pickup systemwith independent volume control means.

In the drawings:

FIG. 1 is a top view of an instrument with this invention;

FIG. 2 is a cross section through 1-1 of FIG. 1 when the basic singlecoil pickup is utilized;

FIG. 3 is a cross section through 1-1 of FIG. 1 when the basic doublecoil pickup is utilized;

FIG. 4 is an illustration of a modified form magnetic circuit which maybe adapted as in FIG. 3; and

FIG. 5 is another illustration of a modified form magnetic circuit whichmay also be adapted as in FIG. 3.

Referring to the drawings, the present invention shown in FIG. 1comprises of a resonator, top, or belly with strings 1 I tensionedbetween suitable tuning means 12, suitable string supporting means 13,and suitable string anchoring means 14.

In FIG. 2, a single coil pickup may be adapted as through 1-1 of FIG. 1.In such case, a magnet is secured to the resonator, top, or belly by anysuitable adhesive means. Further, a hollow core coil 16 of many turns ofmagnet wire is, preferably, adjustably mounted to the instrument back orequivalent thereof 17, by two adjusting screws 18 and 19 which threadinto the coil mounting plate 20. Around each of the aforesaid screws, asuitable resilient means, such as compression springs 21 and 22, areplaced between the said coil plate and the instrument back. Also in FIG.2, a volume control means 23 is illustrated, which may be mounted asindicated by 23 in FIG. 1. Thus in FIG. 2, one end of coil 16 isconnected to ground and one terminal of volume control means 23, whilethe other end of said coil is connected to the sliding an'n terminal ofsaid volume control means and one terminal of a jack 24 which has itsother terminal grounded. Furthermore, the jack 24 may be mounted asindicated by 37 in FIG. 1, and the volume control means 23 may be aconventional potentiometer.

In FIGS. 2, 3, 4, and 5 the letter N indicates a north magneticpolarity, whereas the letter S indicates a south magnetic polarity. Whensuch letters are used on a magnet, they indicate the polarity of themagnet, but when placed near a coil indicate the coil polarity. Further,a minus sign placed near the end of a coil indicates a negative biaspolarity, and a plus sign placed near the other end of the coilindicates a positive bias polarity. 1

In FIG. 3, a double coil pickup may be adapted as through 1 of FIG. 1.In this case, a first magnet 25 is secured to the resonator, top, orbelly 10, and is magnetically linked to a first hollow core coil 26 ofmany turns of magnet wire which is mounted on a coil mounting plate 27.A second magnet 28 is also secured to the said resonator, top, or belly10, and this magnet is magnetically linked to a second hollow core coil29 of many turns of magnet wire which is also mounted on the said coilmounting plate. Preferably, the aforesaid coils are adjustably mountedto the instrument back or equivalent thereof 30, by two adjusting screws31 and 32 which thread into the coil mounting plate 27. Around each ofthe aforesaid adjusting screws, a suitable resilient means, such ascompression springs 33 and 34, are placed between the said coil mountingplate and the instrument back.

Also in FIG. 3, volume control means 23 and 35 are illustrated, and maybe mounted as indicated by 23 and 35 in FIG. 1. Thus, in FIG. 3, one endof a first coil 26 is connected to ground and to one terminal of a firstvolume control means 23, while the other end of the said first coil isconnected to one end of a second coil 29, the sliding terminal of thefirst volume control means 23, and one terminal of a second volumecontrol means 35; and the other end of the second coil 29 is connectedto the sliding terminal of the second volume control means 35 and to oneterminal of a jack 36 which has its other terminal grounded. The jack 36may be mounted as indicated by 37 in FIG. 1, and the volume controlmeans 23 and 35 may be Potentiometers.

FIG. 4 illustrates a modified form magnetic circuit which is asspecified of FIG. 3, except that magnets 37 and 38 oppose each other,and coils 39 and 40 also oppose each other, but each coil aids the fieldof the magnet which it is magnetically linked to.

FIG. 5 illustrates a second modified fonn of magnetic circuit which isas specified of FIG. 3, except that magnets 41 and 42 oppose each other,and coil 43 aids magnet 41, whereas coil 44 opposes magnet 42.

In this patent application, by aiding, it is meant that the magneticfield of the magnets and/or coils attract and have opposite polarity.With such a magnetic configuration, an interference source which wouldbe of the proper polarity to induce hum into the coil is the polaritywhich is opposed by the magnet associated with such coil thus aids ineliminating hum induction. It also results in a greater magnetic fieldand signal output.

Preferably, all magnets described should be Alnico 5 or any suitablemagnetic material with high magnetic properties.

In FIGS. 2, 3, 4, and 5, the magnetic polarity of the magnet and/ormagnets, including the coil and/or coils. may be reversed with no changein results, as long as all the magnet and coil polarities in eachcircuit are reversed. In addition, the pickups in FIGS. 2 and 3 areshown as may be mounted in the area indicated by 1-1 of FIG. 1, but maybe mounted in any area of the instrument which vibrates.

In the operation of the present invention, when any string and/orstrings I 1 are caused to vibrate, this sets the string supporting means13 into motion which in turn causes the resonator 10 to vibrate.

In FIG. 2, when the magnet 15 secured to the said resonator is set intomotion, and/or when magnets 25 and 28 in FIG. 3 are likewise set intomotion, this results in a change in flux linkage through the respectivecoil cores magnetically linked to such magnets. This includes throughcoil 16 in FIG. 2, or through coils 26 and 29 in FIG. 3 etc. to induce avoltage corresponding to the vibration of the strings 11, which may beamplified and reproduced in a well known manner in the art.

In FIGS. 2, 3, and 4, each coil is magnetically linked to its respectivemagnet so as to aid, however it is pointed out that each coil could bemade to oppose its associated magnet as per coil 44 and magnet 42 inFIG. 5.

As shown in FIG. 3, when the resistance of both volume control means 23and 35 are set high compared to the resistance of their associated coils26 and 29, this causes the induced signals to flow toward the amplifierwhich may be linked through the jack 24. Whereas, when the resistance ofboth volume control means 23 and 35 are set at a low resistance comparedto the resistance of their associated coils 26 and 29, said coils arethereby shunted and bypassed. When the resistance of the volume controlmeans, such as 23 and 35 is zero or very low, this completely shunts andbypasses the said coils, and no output from either coil is fed to theamplifier. When the resistance of only one volume control means, such as23 or 35, is zero or very low, this completely shunts only the coilassociated with that particular volume control. Thus, the output of anycoil may be independently controlled without affecting the other norrequiring the use of switches for this purpose. The operation of thevolume control 23 in FIG. 2 is also this type, except only one controlis used, thus needs no further explanation.

With no need for added illustration, it is evident that the output ofeach of the coils 26 and 29 in FIG. 3, and/or each of the two coilsillustrated in FIGS. 4 and 5 may be separately fed to separateamplifiers for stereophonic audio reproduction.

The present invention may also be embodied in semi-hollow type, hollowbody type, flat top type, arched type, as well as right or left handedinstruments. In a piano it may be embodied in both the grand type,upright type, and/or related instruments.

The foregoing is considered as illustrative of the principals of theinvention. Further, since numerous modifications and changes may readilyoccur, it is not desired to limit the invention to the exactconstruction and operation shown and described. Thus all suitablemodifications and equivalents may be resorted to without falling beyondthe scope of the present invention.

I claim: 7

1. In a stringed musical instrument having a resonator, top or bellywith strings tensioned between tuning means, a string supporting means,and a string anchoring means; the improvement comprising: Anelectromagnetic audio pickup including a magnet secured to theresonator, top or belly, and a hollow core coil magnetically linked tosaid magnet, said coil is adjustably mounted to the instrument back by acouple of screws which thread into a coil mounting plate upon which thesaid coil is mounted.

2. The invention specified in claim 1 wherein the said adjusting screwspass through suitable resilient means positioned between the said coilmounting plate and the said instrument back.

3. The invention specified in claim 1 wherein one end of the coil isconnected to ground and to one terminal of a volume control means,whereas the other end of said coil is connected to the sliding terminalof the said volume control means and one terminal of a jack, which hasits other terminal grounded.

4. In a stringed musical instrument having a resonator, top or bellywith strings tensioned between tuning means, a string supporting means,and a string anchoring means; the improvement comprising: Anelectromagnetic audio pickup system ineluding a pair of spaced magnetssecured to a resonator, top or belly which are magnetically linked to apair of spaced hollow core coils which are adjustably mounted to thesaid instrument back, by a couple of screws which thread into a coilmounting plate upon which the said two coils are secured.

5. The invention specified in claim 4 wherein the said adjusting screwspass through suitable resilient means positioned between the said coilmounting plate and the said instrument back.

6. The invention specified in claim 4 wherein one end of a first coil isgrounded and connected to one terminal of a first volume control means,whereas the other end of said first coil is connected to one end of asecond coil, the sliding terminal of the first volume control means, andone tenninal of a second volume control means; and the other end of thesecond coil is connected to the sliding terminal of the second volumecontrol means and to one terminal of a jack, which has its otherterminal grounded.

7. The invention as specified in claim 4 wherein one end of the firstcoil is grounded and connected to one terminal of the first volumecontrol means, while the other end of the first coil is connected to thesliding terminal of the first volume control means which is thereofcoupled to a first amplifier; and one end of the second coil is groundedand connected to one terminal of the second volume control means, whilethe other end of the second coil is connected to the sliding terminal ofthe second volume control means which is thereof coupled to a secondamplifier.

8. The invention specified in claim 4 wherein the pair of spaced hollowcore coils are mounted upon a coil mounting plate.

9. The invention specified in claim 4 wherein the pair of spaced magnetsand counterpart hollow core coils are mounted within the body of theinstrument in a relatively perpendicular axis to the instruments stringaxis.

10. The invention specified in claim 4 wherein the pair of spacedmagnets and counterpart hollow core coils are mounted within the body ofthe instrument in a relatively parallel axis to the instruments stringaxis.

1. In a stringed musical instrument having a resonator, top or bellywith strings tensioned between tuning means, a string supporting means,and a string anchoring means; the improvement comprising: Anelectromagnetic audio pickup including a magnet secured to theresonator, top or belly, and a hollow core coil magnetically linked tosaid magnet, said coil is adjustably mounted to the instrument back by acouple of screws which thread into a coil mounting plate upon which thesaid coil is mounted.
 2. The invention specified in claim 1 wherein thesaid adjusting screws pass through suitable resilient means positionedbetween the said coil mounting plate and the said instrument back. 3.The invention specified in claim 1 wherein one end of the coil isconnected to ground and to one terminal of a volume control means,whereas the other end of said coil is connected to the sliding terminalof the said volume control means and one terminal of a jack, which hasits other terminal grounded.
 4. In a stringed musical instrument havinga resonator, top or belly with strings tensioned between tuning means, astring supporting means, and a string anchoring means; the improvementcomprising: An electromagnetic audio pickup system including a pair ofspaced magnets secured to a resonator, top or belly which aremagnetically linked to a pair of spaced hollow core coils which areadjustably mounted to the said inStrument back, by a couple of screwswhich thread into a coil mounting plate upon which the said two coilsare secured.
 5. The invention specified in claim 4 wherein the saidadjusting screws pass through suitable resilient means positionedbetween the said coil mounting plate and the said instrument back. 6.The invention specified in claim 4 wherein one end of a first coil isgrounded and connected to one terminal of a first volume control means,whereas the other end of said first coil is connected to one end of asecond coil, the sliding terminal of the first volume control means, andone terminal of a second volume control means; and the other end of thesecond coil is connected to the sliding terminal of the second volumecontrol means and to one terminal of a jack, which has its otherterminal grounded.
 7. The invention as specified in claim 4 wherein oneend of the first coil is grounded and connected to one terminal of thefirst volume control means, while the other end of the first coil isconnected to the sliding terminal of the first volume control meanswhich is thereof coupled to a first amplifier; and one end of the secondcoil is grounded and connected to one terminal of the second volumecontrol means, while the other end of the second coil is connected tothe sliding terminal of the second volume control means which is thereofcoupled to a second amplifier.
 8. The invention specified in claim 4wherein the pair of spaced hollow core coils are mounted upon a coilmounting plate.
 9. The invention specified in claim 4 wherein the pairof spaced magnets and counterpart hollow core coils are mounted withinthe body of the instrument in a relatively perpendicular axis to theinstrument''s string axis.
 10. The invention specified in claim 4wherein the pair of spaced magnets and counterpart hollow core coils aremounted within the body of the instrument in a relatively parallel axisto the instrument''s string axis.